[WIP] Add chatbot feature for membership guidance

[Copilot]

Thanks for assigning this issue to me. I'm starting to work on it and will keep this PR's description up to date as I form a plan and make progress.

Original prompt

---

This section details on the original issue you should resolve

<issue_title>:sparkles: [FEAT] 챗봇 기능 추가</issue_title>
<issue_description>## ✨ 어떤 기능인가요?
회비영 어플리케이션 사용법을 알려주는 질의응답 챗봇

📝 작업 상세 내용

• 챗봇 채팅 요청 구현

💡 기대 효과

예) 사용자가 자신의 프로필을 편집할 수 있다

🌐 참고 자료(선택)</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes ✨ [FEAT] 챗봇 기능 추가 #42

---

💬 We'd love your input! Share your thoughts on Copilot coding agent in our 2 minute survey.